| Structural highlights
Disease
APTX_HUMAN Defects in APTX are the cause of ataxia-oculomotor apraxia syndrome (AOA) [MIM:208920. AOA is an autosomal recessive syndrome characterized by early-onset cerebellar ataxia, oculomotor apraxia, early areflexia and late peripheral neuropathy.[1] [2] [3] [4] [5] [6] [7]
Function
APTX_HUMAN DNA-binding protein involved in single-strand DNA break repair, double-strand DNA break repair and base excision repair. Resolves abortive DNA ligation intermediates formed either at base excision sites, or when DNA ligases attempt to repair non-ligatable breaks induced by reactive oxygen species. Catalyzes the release of adenylate groups covalently linked to 5'-phosphate termini, resulting in the production of 5'-phosphate termini that can be efficiently rejoined. Also able to hydrolyze adenosine 5'-monophosphoramidate (AMP-NH(2)) and diadenosine tetraphosphate (AppppA), but with lower catalytic activity.[8] [9] [10] [11] [12]
Publication Abstract from PubMed
Faithful maintenance and propagation of eukaryotic genomes is ensured by three-step DNA ligation reactions used by ATP-dependent DNA ligases. Paradoxically, when DNA ligases encounter nicked DNA structures with abnormal DNA termini, DNA ligase catalytic activity can generate and/or exacerbate DNA damage through abortive ligation that produces chemically adducted, toxic 5'-adenylated (5'-AMP) DNA lesions. Aprataxin (APTX) reverses DNA adenylation but the context for deadenylation repair is unclear. Here we examine the importance of APTX to RNase-H2-dependent excision repair (RER) of a lesion that is very frequently introduced into DNA, a ribonucleotide. We show that ligases generate adenylated 5' ends containing a ribose characteristic of RNase H2 incision. APTX efficiently repairs adenylated RNA-DNA, and acting in an RNA-DNA damage response (RDDR), promotes cellular survival and prevents S-phase checkpoint activation in budding yeast undergoing RER. Structure-function studies of human APTX-RNA-DNA-AMP-Zn complexes define a mechanism for detecting and reversing adenylation at RNA-DNA junctions. This involves A-form RNA binding, proper protein folding and conformational changes, all of which are affected by heritable APTX mutations in ataxia with oculomotor apraxia 1. Together, these results indicate that accumulation of adenylated RNA-DNA may contribute to neurological disease.
Aprataxin resolves adenylated RNA-DNA junctions to maintain genome integrity.,Tumbale P, Williams JS, Schellenberg MJ, Kunkel TA, Williams RS Nature. 2013 Dec 22. doi: 10.1038/nature12824. PMID:24362567[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Date H, Onodera O, Tanaka H, Iwabuchi K, Uekawa K, Igarashi S, Koike R, Hiroi T, Yuasa T, Awaya Y, Sakai T, Takahashi T, Nagatomo H, Sekijima Y, Kawachi I, Takiyama Y, Nishizawa M, Fukuhara N, Saito K, Sugano S, Tsuji S. Early-onset ataxia with ocular motor apraxia and hypoalbuminemia is caused by mutations in a new HIT superfamily gene. Nat Genet. 2001 Oct;29(2):184-8. PMID:11586299 doi:10.1038/ng1001-184
- ↑ Moreira MC, Barbot C, Tachi N, Kozuka N, Uchida E, Gibson T, Mendonca P, Costa M, Barros J, Yanagisawa T, Watanabe M, Ikeda Y, Aoki M, Nagata T, Coutinho P, Sequeiros J, Koenig M. The gene mutated in ataxia-ocular apraxia 1 encodes the new HIT/Zn-finger protein aprataxin. Nat Genet. 2001 Oct;29(2):189-93. PMID:11586300 doi:10.1038/ng1001-189
- ↑ Shimazaki H, Takiyama Y, Sakoe K, Ikeguchi K, Niijima K, Kaneko J, Namekawa M, Ogawa T, Date H, Tsuji S, Nakano I, Nishizawa M. Early-onset ataxia with ocular motor apraxia and hypoalbuminemia: the aprataxin gene mutations. Neurology. 2002 Aug 27;59(4):590-5. PMID:12196655
- ↑ Tranchant C, Fleury M, Moreira MC, Koenig M, Warter JM. Phenotypic variability of aprataxin gene mutations. Neurology. 2003 Mar 11;60(5):868-70. PMID:12629250
- ↑ Le Ber I, Moreira MC, Rivaud-Pechoux S, Chamayou C, Ochsner F, Kuntzer T, Tardieu M, Said G, Habert MO, Demarquay G, Tannier C, Beis JM, Brice A, Koenig M, Durr A. Cerebellar ataxia with oculomotor apraxia type 1: clinical and genetic studies. Brain. 2003 Dec;126(Pt 12):2761-72. Epub 2003 Sep 23. PMID:14506070 doi:10.1093/brain/awg283
- ↑ Criscuolo C, Mancini P, Menchise V, Sacca F, De Michele G, Banfi S, Filla A. Very late onset in ataxia oculomotor apraxia type I. Ann Neurol. 2005 May;57(5):777. PMID:15852392 doi:10.1002/ana.20463
- ↑ Quinzii CM, Kattah AG, Naini A, Akman HO, Mootha VK, DiMauro S, Hirano M. Coenzyme Q deficiency and cerebellar ataxia associated with an aprataxin mutation. Neurology. 2005 Feb 8;64(3):539-41. PMID:15699391 doi:10.1212/01.WNL.0000150588.75281.58
- ↑ Sano Y, Date H, Igarashi S, Onodera O, Oyake M, Takahashi T, Hayashi S, Morimatsu M, Takahashi H, Makifuchi T, Fukuhara N, Tsuji S. Aprataxin, the causative protein for EAOH is a nuclear protein with a potential role as a DNA repair protein. Ann Neurol. 2004 Feb;55(2):241-9. PMID:14755728 doi:10.1002/ana.10808
- ↑ Gueven N, Becherel OJ, Kijas AW, Chen P, Howe O, Rudolph JH, Gatti R, Date H, Onodera O, Taucher-Scholz G, Lavin MF. Aprataxin, a novel protein that protects against genotoxic stress. Hum Mol Genet. 2004 May 15;13(10):1081-93. Epub 2004 Mar 25. PMID:15044383 doi:10.1093/hmg/ddh122
- ↑ Kijas AW, Harris JL, Harris JM, Lavin MF. Aprataxin forms a discrete branch in the HIT (histidine triad) superfamily of proteins with both DNA/RNA binding and nucleotide hydrolase activities. J Biol Chem. 2006 May 19;281(20):13939-48. Epub 2006 Mar 16. PMID:16547001 doi:M507946200
- ↑ Ahel I, Rass U, El-Khamisy SF, Katyal S, Clements PM, McKinnon PJ, Caldecott KW, West SC. The neurodegenerative disease protein aprataxin resolves abortive DNA ligation intermediates. Nature. 2006 Oct 12;443(7112):713-6. Epub 2006 Sep 10. PMID:16964241 doi:10.1038/nature05164
- ↑ Rass U, Ahel I, West SC. Actions of aprataxin in multiple DNA repair pathways. J Biol Chem. 2007 Mar 30;282(13):9469-74. Epub 2007 Feb 2. PMID:17276982 doi:M611489200
- ↑ Tumbale P, Williams JS, Schellenberg MJ, Kunkel TA, Williams RS. Aprataxin resolves adenylated RNA-DNA junctions to maintain genome integrity. Nature. 2013 Dec 22. doi: 10.1038/nature12824. PMID:24362567 doi:http://dx.doi.org/10.1038/nature12824
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